The parent grant for this application is project 3 "Epidermal Growth Factor Regulator of Phospholipase C-gamma1" with a Program Project Grant "Mechanism of Action of Epidermal Growth Factor" (CA43720) which is funded until December 31, 1996. Dr. Carpenter is the principal investigator of the Program Project and project 3. The proposed work in the application takes advantage of Dr. Hernandez' training and experience with phospholipase C and seeks to uncover novel mechanisms of PLC regulation in plants. Although PLC enzymes in animals and plants catalyze the same basic reaction, the plant systems offer a novel biological system in which a differentiated organism can be routinely generated in the laboratory from undifferentiated cells. Comparative studies at both the biological and enzymological level are proposed to be useful to understand more completely the role of PLCs in nature and signal transduction relevant to growth. Dr. Carpenter's grant proposes no plant studies and the overlap of aims exists only at the level of reagents and enzyme assays.